MUNCIE – A local man acknowledged he left a backpack full of materials used in the production of meth last week in a restroom at the south Muncie Walmart store.

But Tyler Justin Armstrong, 25 — listed as homeless on court documents — maintained he was not trying to “cook” meth in the store.

Armstrong, taken into custody Monday night after fighting with police at a southside restaurant, said he left the backpack in the store restroom on the evening of March 12 because a container of “Liquid Lightning” drain cleaner was leaking “through the (backpack), burning him.”

Reports on the discovery of the meth “lab” in the Walmart restroom last week brought Muncie national — if undesirable — attention, and went “viral” on the Internet.

Armstrong— preliminarily charged with aiding in the manufacture of meth, dumping controlled substance waste, battery on a police officer and resisting law enforcement — remained in the Delaware County jail on Monday night under a $30,000 bond.

Interviewed by state police late Monday at the jail, Armstrong acknowledged he and another man had been at the southside Walmart store on March 11 to buy fuel and tubing, both for use in meth production.

An affidavit reflects Armstrong returned to the Walmart the next night, apparently to buy more drain cleaner, but then abandoned his red and black Adidas backpack — stocked with various items and equipment used in “cooking” meth — in the restroom when he left the store.

State police identified Armstrong through Walmart surveillance video of his March 11-12 visits to the store. On Monday evening, they saw him and an associate — Ashley Elizabeth Oliver, 24, also of Muncie — at the Taco Bell at 2201 S. Madison St.

Armstrong tried to flee when troopers approached him in a restaurant restroom, and an ensuing fight lasted up to eight minutes, the affidavit said. A Taco Bell employee helped troopers as they struggled to handcuff the suspect, who was found to have a knife in his pocket.

Authorities said they also found a notepad listing meth ingredients, and a box of an over-the-counter cold medication used in meth cooking — purchased a few minutes earlier at a southside pharmacy — in Armstrong’s possession.

Meth-related materials were also found in Oliver’s purse, troopers wrote.

Oliver reportedly told the troopers that Armstrong and another man had “cooked” meth as recently as Sunday night.

The Muncie woman, preliminarily charged with aiding in the manufacture of meth, was being held in the jail Tuesday night under a $5,000 bond.

According to Delaware County court records, Armstrong was convicted of possession of a controlled substance in 2012 and public intoxication in 2011.

The men’s restroom at the southside Walmart, and a nearby women's restroom, have remained closed since last week by order of the Delaware County Health Department.

Brian Nick, director of national media relations for Walmart, said Monday the store's restrooms had been cleaned by a professional crew, but would not reopen until testing of the facilities is completed.

Contact news reporter Douglas Walker at (765) 213-5851. You can also follow him on Twitter @DouglasWalkerSP.